1. INTRODUCTION

1.1. OVERVIEW

This manual describes the AT commands for the following Rockwell modem
families:

RC96V24AC and RC14V24AC

RC96ACW and RC144ACW

RC96ACL/RC144ACL and RC96ACi/RC144ACi

The descriptions apply to all these modems with any differences between
modem product families noted.

1.1.1. Command Syntax

The fundamental DTE interface command syntax is described in Section 2.

1.1.2. Command Descriptions

These commands are grouped into the following categories:

AT commands Section 3

S Registers Section 4

V.25 commands Section 5

Fax Class 1 commands Section 6

Fax Class 2 commands Section 7

Voice commands Section 8

The AT commands are implemented in microcontroller (MCU) firmware for
specific modem models. The support for a command category
is identified by modem model in the modem designer's guide. Additional
configuration and implementation information is available
in release notes and/or readme files that accompany MCU firmware release.

1.1.3. Call Progress and Blacklisting Parameters

The modem MCU firmware may be provided either in reconfigurable form or
preconfigured form. Consult the specific firmware release
notes for exact configuration information.
Reconfigurable Form. The modem MCU firmware can configured for operation
inspecific countries by the PC-compatible ConfigurACE II program. The call
progress and blacklisting parameters described the
ConfigurACE II User's Manual can be altered and loaded
for a number of countries by this program. Serial or parallel interface
operation may also be selectable.
Preconfigured Form. Specific MCU firmware configurations may be released
that can be directly installed without requiring the
use of ConfigurACE II.

1.1.4. ConfigurACE II

The ConfigurACE II User's Manual describes the use of ConfigurACE II and
the country modifiable parameters. Consult any readme
files accompanying the ConfigurACE II program for additional or later
information.

2. COMMAND SYNTAX

2.1. DTE/DCE INTERCHANGE CIRCUITS

Communication between the DTE and modem is half duplex (i.e., only one
entity 'talks' at a time).

2.2. COMMAND SYNTAX AND GUIDELINES

2.2.1. DTE Commands

The ISO 646 character set (CCITT T.50 International Alphabet 5, American
Standard Code for Information Interchange) is used
for the issuance of commands and responses. Only the low-order 7 bits of
each character are used for commands or parameters;
the high-order bit is ignored. Upper case characters are equivalent to
lower case characters.

2.2.2. DTE Command Lines

A command line is a string of characters sent from a DTE to the DCE while
the DCE is in a command state. Command lines have
a prefix, a body, and a terminator. The prefix consists of the ASCII
characters "AT" (065, 084) or "at" (097, 116). The body
is a string of commands restricted to printable ASCII characters (032 -
126). Control characters other than CR (ASCII 013)
and BS (ASCII 010) in the command string are ignored. The default
terminator is the ASCII character. Characters that precede
the AT prefix are ignored.

2.3.1. Basic Command Syntax

Characters within the command line are parsed as commands with associated
parameter values. The basic commands consist of single
ASCII characters, or single characters preceded by a prefix character
(e.g. , "&"), followed by a decimal parameter.

Missing decimal parameters are evaluated as 0.

2.3.2. Extended Command Syntax

The facsimile commands use extended syntax. They are preceded by the "+F"
characters, and they are terminated by the semicolon
":" character (ASCII 059) or by the that terminates the command line.

3. AT COMMAND SET

3.1. AT COMMAND GUIDELINES

The basic AT commands used to control modem operation are defined in this
section. These commands are summarized in Appendix
A. All these commands may not be available in a specific product depending
upon supported data rates and modes (data/fax/voice,
error correction, data compression, and data throughput enhancement). The
default values are typical of a fully configured
modem supporting all data rates, modes, and options. The actual default
value is dependent upon modem firmware as defined by
the firmware release notes.

3.1.1. AT Commands, DTE Adaption

Under AT operation, the serial interfaced modem performs an
autobaud/autoparity/autolength function on each AT header entered.
The autolength/autoparity facility can detect 7- or 8-bit characters of
even, odd, or no parity with one stop bit. This is
not necessary for the parallel interfaced modem since it has direct access
to the UART registers.

3.1.2. AT Command Format

Under the AT command set (with the exception of the A/ command), each
command line sent by the DTE must begin with the character
sequence AT and must be terminated by a carriage return. Commands entered
in upper case or lower case are accepted, but both
the A and T must be of the same case. The command line interpretation
begins upon receipt of the carriage return character.

The modem supports the editing of command lines by recognizing a backspace
character. When modem echo is enabled, the modem
responds to receipt of a backspace or delete by echoing a backspace
character, a space character, and another backspace. The
hex value to be used for the backspace character is programmable through
register S5. Values equal to 0 or greater than 127,
or the value which corresponds to the carriage return character, cannot be
used for the backspace character. This editing is
not applicable to the AT header of a command. A command line may be
aborted at any time by entering < cntrl-x > (18h).

The AT sequence may be followed by any number of commands in sequence,
except for commands such as Z, D, or A. Commands following
commands Z, D, or A on the same command line will be ignored. The maximum
number of characters on any command line is 256 (including
"A" and "T"). If a syntax error is found anywhere in a command line
command, the remainder of the line will be ignored and
the ERROR result code will be returned.

Most commands entered with parameters out of range will not be accepted
and the ERROR response will be returned to the DTE.

Commands will only be accepted by the modem once the previous command has
been fully executed, which is normally indicated
by the return of an appropriate result code. Execution of commands D and
A, either as a result of a direct command or a re
execute command, will be aborted if another character is entered before
completion of the handshake.

3.1.3. Escape Code Sequence

When the modem has established a connection and has entered on-line data
mode, it is possible to break into the data transmission
in order to issue further commands to the modem in an on-line command
mode. This is achieved by the DTE sending to the modem
a sequence of three ASCII characters specified by register S2. The default
character is '+'. The timing of the three characters
must comply with specific time constraints. There is a guard time before
the first character (the pre-sequence time), a guard
time following the third character (the post-sequence time), and a guard
time-out between the first and second characters and
between the second and third characters (the inter-character time). These
times are controlled by the value recorded in register
S12.

3.2. AT COMMAND SET

The modem will respond to the commands detailed below. Parameters
applicable to each command are listed with the command description.
The defaults shown for each configuration command are those used in the
Rockwell factory profile 0.

3.2.1. AT Commands

A/ - Re-execute Command

The modem behaves as though the last command line had been re-sent by the
DTE. "A/" will repeat all the commands in the command
buffer.

The principle application of this command is to place another call (using
the Dial command) that failed to connect due to a
busy line, no answer, or a wrong number. This command must appear alone on
a command line and must be terminated by the "/"
character. This command should not be terminated by a carriage return.

AT= x - Write to Selected S-Register

This command writes the value x to the currently selected S-register. An
S-register can be selected by using the ATSn command.
All of the S-registers will return the OK response if x is a number. Some
registers may not be written due to country specific
PTT limitations.

Result Codes

OK For all arguments.

AT? - Read Selected S-Register

This command reads and displays the selected S-register. An S-register can
be selected by using the ATSn command.

Result Codes:

OK For all arguments.

A - Answer

The modem will go off-hook and attempt to answer an incoming call if
correct conditions are met. Upon successful completion
of answer handshake, the modem will go on-line in answer mode. This
command may be affected by the state of Line Current Sense,
if enabled. (Most countries do not require Line Current Sense.) Operation
is also dependent upon +FCLASS command and country
specific requirements.

If +FCLASS=0 is selected, the modem will enter the connect state after
exchanging carrier with the remote modem. If no carrier
is detected within a period specified in register S7, the modem hangs up.
Any character entered during the connect sequence
will abort the connection attempt.

If +FCLASS=1 or 2 is selected, the modem will go off-hook in V.21 answer
mode. It will generate the V.21 2100 Hz answer tone
for 3 =F1 0.5 seconds and, following a delay of 70 ms, will proceed as if
the +FTH=3 command were issued. At any stage up to
(but excluding) the +FTH=3 command state, any character will abort the
communication. (See the description of the +FTH command
for details.)

Bn - CCITT or Bell

When the modem is configured to allow either option, the modem will select
Bell or CCITT modulation for a line speed connection
of 300 or 1200 bps according to the parameter supplied. Any other line
speed will use a CCITT modulation standard. The parameter
value, if valid, is written to S27 bit 6. (Also, see ATFn command.)

B0 Selects CCITT operation at 300 or 1200 bps during Call Establishment
and a subsequent connection. (Default for W-class models.)

B1 Selects BELL operation at 300 or 1200 bps during Call Establishment and
a subsequent connection. (Default for US models.)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

Cn - Carrier Control

This command is included for compatibility only, and has no effect other
than returning a result code. The only valid parameter
is 1.

Result Codes:

OK n = 1.
ERROR Otherwise.

Dn - Dial

This command directs the modem to go on-line, dial according to the string
entered and attempt to establish a connection. If
no dial string is supplied, the modem will go on-line and attempt the
handshake in originate mode. In W-class models, the action
of going off-hook is affected by the status of the Line Current Sense
input, if line current sensing is enabled, and by the
blacklist and delayed list. NOTE: If the ATD command is issued before the
S1 register has cleared, the modem will respond with
the NO CONNECT result code.

If +FCLASS=0 is selected, the modem will behave as a data modem and will
attempt to connect to another data modem. The modem
will have up to the period of time specified by register S6 or S7 to wait
for carrier and complete the handshake. If this time
expires before the modem can complete the handshake, the modem will go
on-hook with the NO CARRIER response. This command will
be aborted in progress upon receipt of any DTE character before completion
of the handshake.

If +FCLASS=1 or 2 is selected, the modem will behave as a facsimile
modem and attempt to connect to a facsimile machine (or
modem) by entering the HDLC V.21 channel 2 receive state (as if +FRH=3
had been issued). This command will be aborted upon
receipt of any DTE character if the modem has not finished dialing. In
this case, the modem will go on-hook and return to command
mode after displaying the NO CARRIER message. If the modem has finished
dialing, it proceeds as if the +FRH=3 command has been
issued. (Refer to the +FRH command to determine how the modem behaves
following this stage.)

Dial Modifiers. The valid dial string parameters are described below.
Punctuation characters may be used for clarity, with
parentheses, hyphen, and spaces being ignored.

0-9

DTMF digits 0 to 9.

*

The 'star' digit (tone dialling only).

#

The 'gate' digit (tone dialling only).

A-D

DTMF digits A, B, C, and D. Some countries may prohibit sending of
these digits during dialing.

Re-dial last number: the modem will re-dial the last valid telephone
number. The L must be immediately after the D with all
the following characters ignored).

P

Select pulse dialling: pulse dial the numbers that follow until a "T" is
encountered. Affects current and subsequent dialling.
Some countries prevent changing dialling modes after the first digit is
dialled.

T

Select tone dialling: tone dial the numbers that follow until a "P" is
encountered. Affects current and subsequent dialling.
Some countries prevent changing dialling modes after the first digit is
dialled.

R

This command will be accepted, but not acted on.

S=n

Dial the number stored in the directory (n = 0 to 19). (See &Z.)

!

Flash: the modem will go on-hook for a time defined by the value of S29.
Country requirements may limit the time imposed.

W

Wait for dial tone: the modem will wait for dial tone before dialling
the digits following "W". If no dial tone is detected
within the time specified by S7 (US models) or S6 (W-class models), the
modem will abort the rest of the sequence, return on
hook, and generate an error message.

@

Wait for silence: the modem will wait for at least 5 seconds of silence
in the call progress frequency band before continuing
with the next dial string parameter. If the modem does not detect these 5
seconds of silence before the expiration of the call
abort timer (S7), the modem will terminate the call attempt with a NO
ANSWER message. If busy detection is enabled, the modem
may terminate the call with the BUSY result code. If answer tone arrives
during execution of this parameter, the modem handshakes.

,

Dial pause: the modem will pause for a time specified by S8 before
dialling the digits following ",".

;

Return to command state. Added to the end of a dial string, this causes
the modem to return to the command state after it
processes the portion of the dial string preceding the ";". This allows
the user to issue additional AT commands while remaining
off-hook. The additional AT commands may be placed in the original command
line following the ";" and/or may be entered on
subsequent command lines. The modem will enter call progress only after an
additional dial command is issued without the ";"
terminator. Use "H" to abort the dial in progress, and go back on-hook.

^

Disable calling tone: applicable to current dial attempt only.

( )

Ignored: may be used to format the dial string.

-

Ignored: may be used to format the dial string.

<space>

Ignored: may be used to format the dial string.

<i>

Invalid character: will be ignored.

>

If enabled by country specific parameter, the modem will generate a
grounding pulse on the EARTH relay output.

En - Command Echo

The modem enables or disables the echo of characters to the DTE according
to the parameter supplied. The parameter value, if
valid, is written to S14 bit 1.

E0

Disables command echo.

E1

Enables command echo. (Default.)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

Fn - Select Line Modulation

This command selects the line modulation according to the parameter
supplied. The line modulation is fixed unless automode
is selected. This command interacts with the S37 and the N command. The
parameter value, if valid, is written to S31 bit 1.
To select line modulation, it is recommended that either the F command, or
a combination of the S37 and the N command, be used,
but not both.

F0

Selects auto-detect mode . Sets N1 and sets S31 bit 1. In this mode,
the modem configures for automode operation. All connect
speeds supported by the modem are possible according to the remote modem's
preference. The contents of S37 are ignored as is
the sensed DTE speed.

F1

Selects V.21 or Bell 103 according to the B setting as the only
acceptable line speed resulting in a subsequent connection.
Sets N0, sets S37 to 1, and clears S31 bit 1. This command is equivalent
to the command string: ATN0S37=1.

F2

Not supported. (Other Rockwell products use this setting for 600 bps.)

F3

Selects V.23 as the only acceptable line modulation for a subsequent
connection. Originator is at 75 bps and answerer is
at 1200 bps. Sets N0, sets S37 to 7, and clears S31 bit 1. This command is
equivalent to the command string: ATN0S37=7.

F4

Selects V.22 1200 or Bell 212A according to the B command setting as
the only acceptable line speed for a subsequent connection.
Sets N0, sets S37 to 5, and clears S31 bit 1. This command is equivalent
to the command string: ATN0S37=5.

F5

Selects V.22 bis as the only acceptable line modulation for a
subsequent connection. Sets N0, sets S37 to 6, and clears
S31 bit 1. This command is equivalent to the command string: ATN0S37=6.

F6

Select V.32 bis 4800 or V.32 4800 as the only acceptable line
modulation for a subsequent connection. Sets N0, sets S37
to 8, and clears S31 bit 1. This command is equivalent to the command
string: ATN0S37=8.

F7

Selects V.32 bis 7200 as the only acceptable line modulation for a
subsequent connection. Sets N0, sets S37 to 12, and clears
S31 bit 1. This command is equivalent to the command string: ATN0S37=12.

This setting also allows connection at the Rockwell proprietary 7200 V.32
speed, e.g., with a RC9696/12 based modem.

F8

Selects V.32 bis 9600 or V.32 9600 as the only acceptable line
modulations for a subsequent connection. Sets N0, sets S37
to 9, and clears S31 bit 1. This command is equivalent to the command
string: ATN0S37=9.

F9

Selects V.32 bis 12000 as the only acceptable line modulation for a
subsequent connection. Sets N0, sets S37 to 10, and
clears S31 bit 1. This command is equivalent to the command string:
ATN0S37=10.

This setting also allows connection at the Rockwell proprietary 12000
V.32 speed, e.g., with a RC9696/12 based modem.

F10

Selects V.32 bis 14400 as the only acceptable line modulation for a
subsequent connection. Sets N0, sets S37 to 11, and
clears S31 bit 1. This command is equivalent to the command string:
ATN0S37=11.

Hn - Disconnect (Hang-Up)

This command initiates a hang up sequence.

This command may not be available for some countries due to PTT
restrictions.

H0

The modem will release the line if the modem is currently on-line, and
will terminate any test (AT&T) that is in progress.
Country specific, modulation specific, and error correction protocol
specific (S38) processing is handled outside of the H0
command.

H1

If on-hook, the modem will go off-hook and enter command mode. The
modem will return on-hook after a period of time determined
by S7.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

In - Identification

The modem reports to the DTE the requested result according to the command
parameter.

I0

Reports product code (e.g., "14400").

I1

Reports pre-computed checksum from ROM (e.g., "007").

I2

Computes checksum and compares it with value stored in ROM. Reports
result as OK or ERROR.

Result Codes:

Ln - Speaker Volume

The modem sets the speaker volume control according to the parameter
supplied. The parameter value, if valid, is written to
S22 bits 0 and 1.

L0

Low volume.

L1

Low volume. (Default.)

L2

Medium volume.

L3

High volume.

Result Codes:

OK n = 0 to 3.
ERROR Otherwise.

Mn - Speaker Control

This command selects when the speaker will be on or off. The parameter
value, if valid, is written to S22 bits 2 and 3.

M0

Speaker is always off.

M1

Speaker is on during call establishment, but off when receiving
carrier. (Default.)

M2

Speaker is always on.

M3

Speaker is off when receiving carrier and during dialling, but on
during answering.

Result Codes:

OK n = 0 to 3.
ERROR Otherwise.

Nn - Automode Enable

This command enables or disables automode detection. The parameter value,
if valid, is written to S31 bit 1.

N0 Automode detection is disabled. A subsequent handshake will be
conducted according to the contents of S37 or, if S37 is
zero, according to the most recently sensed DTE speed.

N1

Automode detection is enabled. A subsequent handshake will be conducted
according to the automode algorithm supported by
the modem. This command is equivalent to F0. (Default.)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

On - Return to On-Line Data Mode

This command determines how the modem will enter the on-line data mode. If
the modem is in the on-line command mode, the enters
the on-line data mode with or without a retrain. If the modem is in the
off-line command mode (no connection), ERROR is reported.

O0

Enters on-line data mode without a retrain. Handling is determined by
the Call Establishment task. Generally, if a connection
exists, this command connects the DTE back to the remote modem after an
escape (+++).

O1

Enters on-line data mode with a retrain before returning to on-line
data mode.

Result Codes:

OK n = 0 or 1 and a connection exists.
ERROR Otherwise or if not connected.

P - Set Pulse Dial Default

This command forces pulse dialing until the next T dial modifier or T
command is received. Sets S14 bit 5.

As soon as a dial command is executed which explicitly specifies the
dialling mode for that particular call (e.g., ATDT...),
this command is overridden so that all future dialling will be tone
dialled. (See T command.)

This command may not be permitted in some countries.

Result Code:

OK

Qn - Quiet Results Codes Control

The command enables or disables the sending of result codes to the DTE
according to the parameter supplied. The parameter value,
if valid, is written to S14.

Q0

Enables result codes to the DTE. (Default.)

Q1

Disables result codes to the DTE.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

Sn - Read/Write S-Register

The modem selects an S-register, performs an S-register read or write
function, or reports the value of an S-register.

n

Establishes S-register n as the default register.

n=v

Sets S-register n to the value v.

n?

Reports the value of S-register n.

The parameter n can be omitted, in which case S0 will be assumed. The S
can be omitted in which case the last s-register accessed
(default register) will be assumed.

For example:

ATS7 establishes S7 as the default register.
ATS38 establishes S38 as the default register.
AT=40 sets the contents of the default register to 40.
ATS sets the contents of S0 to 20.

If the number "n" is beyond the range of the S-registers available, the
modem will return the ERROR message. The value "v"
is "MOD"ed with 256. If the result is outside the range permitted for a
given S-register the values will still be stored, but
functionally the lower and higher limits will be observed. Input and
output are always in decimal format. Note that some S
registers are read-only.

In some cases, writing to the S register will appear to be accepted but
the value will not actually be written.

Due to country restrictions, some commands will be accepted, but the value
may be limited and replaced by a maximum or minimum
value.

Minimum, maximum, and default values for S-registers may be altered with
ConfigurACE.

T - Set Tone Dial Default

This command forces DTMF dialing until the next P dial modifier or P
command is received. The modem will set an S register
bit to indicate that all subsequent dialling should be conducted in tone
mode. Note that the DP command will override this
command. Clears S14 bit 5.

This command may not permitted in some countries. (See P.)

Result Code:

OK

Vn - Result Code Form

This command selects the sending of short-form or long-form result codes
to the DTE. The parameter, if valid, is written to
S14 bit 3.

V0

Enables short-form (terse) result codes. Line feed is not issued before
a short-form result code.

V1

Enables long-form (verbose) result codes. (Default.)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

Wn - Error Correction Message Control.

This command controls the format of CONNECT messages. The parameter value,
if valid, is written to S31 bits 2 and 3. (Also,
see S95 description.)

Result Codes:

OK n = 0, 1, or 2.
ERROR Otherwise.

Xn - Extended Result Codes:

This command selects which subset of the result messages will be used by
the modem to inform the DTE of the results of commands.

Blind dialling is enabled or disabled by country parameters. If the user
wishes to enforce dial tone detection, a "W" can be
placed in the dial string (see D command). Note that the information below
is based upon the default implementation of the
X results table. Table 3-1 indicates the messages which are enabled for
each X value.

If the modem is in facsimile mode (+FCLASS=1 or 2), the only message
sent to indicate a connection is CONNECT without a speed
indication.

X0

Disables monitoring of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, and NO ANSWER result codes. Blind dialling enabled/disabled by
country parameters. If busy tone detection is enforced
and busy tone is detected, NO CARRIER will be reported. If dial tone
detection is enforced or selected and dial tone is not
detected, NO CARRIER will be reported instead of NO DIAL TONE. The value
000b is written to S22 bits 6, 5, and 4, respectively.

X1

Disables monitoring of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, NO ANSWER, and CONNECT XXXX (XXXX = rate). Blind dialling
enabled/disabled by country parameters. If busy tone detection
is enforced and busy tone is detected, NO CARRIER will be reported instead
of BUSY. If dial tone detection is enforced or selected
and dial tone is not detected, NO CARRIER will be reported instead of NO
DIAL TONE. The value 100b is written to S22 bits 6,
5, and 4, respectively.

X2

Disables monitoring of busy tones unless forced otherwise by country
requirements; send only OK, CONNECT, RING, NO CARRIER,
ERROR, NO DIALTONE, NO ANSWER, and CONNECT XXXX. If busy tone detection is
enforced and busy tone is detected, NO CARRIER will
be reported instead of BUSY. If dial tone detection is enforced or
selected and dial tone is not detected, NO DIAL TONE will
be reported instead of NO CARRIER . The value 101b is written to S22 bits
6, 5, and 4, respectively.

X3

Enables monitoring of busy tones; send only OK, CONNECT, RING, NO
CARRIER, ERROR, NO ANSWER, and CONNECT XXXX. Blind dialling
enabled/disabled by country parameters. If dial tone detection is enforced
and dial tone is not detected, NO CARRIER will be
reported. The value 110b is written to S22 bits 6, 5, and 4, respectively.

X4

Enables monitoring of busy tones; send all messages. The value 111b is
written to S22 bits 6, 5, and 4, respectively. (Default.)

Yn - Long Space Disconnect

This command enables/disables the generation and response to long space
disconnect. The parameter value, if valid, is written
to S21 bit 7.

Y0

Disables long space disconnect. (default.)

Y1

Enables long space disconnect. In non-error correction mode, the modem
will send a long space of four seconds prior to going
on-hook. In error correction mode, the modem will respond to the receipt
of a long space (i.e., a break signal greater than
1.6 seconds) by going on-hook.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

Zn - Soft Reset and Restore Profile

The modem performs a soft reset and restores (recalls) the configuration
profile according to the parameter supplied. If no
parameter is specified, zero is assumed.

Z0

Soft reset and restore stored profile 0.

Z1

Soft reset and restore stored profile 1.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.2.2. AT& Commands

&Cn - RLSD (DCD) Option

The modem controls the RLSD output in accordance with the parameter
supplied. The parameter value, if valid, is written to
S21 bit 5.

&C0

RLSD remains ON at all times. (Default.)

&C1

RLSD follows the state of the carrier.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Dn - DTR Option

This command interprets the ON to OFF transition of the DTR signal from
the DTE in accordance with the parameter supplied.
The parameter value, if valid, is written to S21 bits 3 and 4.

&D0

DTR drop is interpreted according to the current &Q setting as
follows: (Default.)

DTR drop is interpreted according to the current &Q setting as follows:

&Q0, &Q1, &Q4, &Q5, &Q6

DTR drop is interpreted by the modem as if the
asynchronous escape sequence had been entered. The modem
returns to asynchronous command state without disconnecting.

&Q2, &Q3

DTR drop causes the modem to hang up. Auto-answer is inhibited.

&D2

DTR drop is interpreted according to the current &Q setting as follows:

&Q0 through &Q6

DTR drop causes the modem to hang up. Auto-answer is
inhibited.

&D3

DTR drop is interpreted according to the current &Q setting as follows:

&Q0, &Q1, &Q4, &Q5, &Q6

DTR drop causes the modem to perform a soft reset
as if the Z command were received. The &Y setting
determines which profile is loaded.

&Q2, &Q3

DTR drop causes the modem to hang up. Auto-answer is inhibited.

If &Q5, &Q6, +FCLASS=1 or +FCLASS=2 is in effect, the action taken is
the same as for &Q0.

&F - Restore Factory Configuration (Profile)

The modem loads the factory default configuration profile. The factory
defaults are identified for each command and in the
S register descriptions. A configuration profile consists of a subset of
S-registers.

&F Restore Factory Configuration

Result Codes:

OK
ERROR If the modem is connected.

&Gn - Select Guard Tone

The modem generates the guard tone selected by this command according to
the parameter supplied (DPSK modulation modes only).
The parameter value, if valid, is written to S23 bits 6 and 7.

&G0

Disables guard tone. (Default for US models.)

&G1

Disables guard tone.

&G2

Selects 1800 Hz guard tone. (Default for W-class models.)

This command may not be permitted in some countries.

Result Codes:

OK n = 0 to 2.
ERROR Otherwise.

&Jn - Telephone Jack Control

This command is only included for compatibility and performs no function
except to load the S-register. The parameter value,
if valid, is written S21 bit 1.

&J0

&J0 command. (Default.)

&J1

&J1 command.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Kn - Flow Control

This command defines the DTE/DCE (terminal/modem) flow control mechanism.
The parameter value, if valid, is written to S39
bits 0, 1, and 2.

&K0

Disables flow control.

&K3

Enables RTS/CTS flow control. (Default for data modem modes.)

&K4

Enables XON/XOFF flow control.

Result Codes:

OK n = 0, 3, or 4.
ERROR Otherwise.

&Ln - Leased Line Operation

This command selects leased or dial-up line operation for compatibility.
The OK response is returned for a valid parameter,
but no other action is performed. The parameter value, if valid, is
written to S27 bit 2.

&L0

Selects dial-up line operation.

&L1

Selects leased line operation.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Mn - Asynchronous/Synchronous Mode Selection

This command determines the DTR operating mode. The modem treats the &M
command as a subset of the &Q command.

&M0

Selects direct asynchronous operation. Note that the command sequence
&M0\N0 selects normal buffered mode, but the command
sequence \N0&M0 selects direct mode. This is because the \N0 command is
analogous to the &Q6 command. The value 000b is written
to S27 bits 3, 1, and 0, respectively. (See &Q).

Selects synchronous connect mode with async off-line command mode.
Same as &M1 except that &M2 enables DTR dialling of
directory slot 0. The modem will disconnect if DTR is OFF for more than
the period in S25 (in units of hundredths of a second):
the data connection will be synchronous. The value 010b is written to S27
bits 3, 1, and 0, respectively.

&M3

Selects synchronous connect mode. This mode allows DTR to act as a
talk/data switch. The call is manually initiated while
DTR is inactive. When DTR becomes active, the handshake proceeds in
originate or answer mode according to S14 bit 7. The value
011b is written to S27 bits 3, 1, and 0, respectively.

Result Codes:

OK n = 0 to 3.
ERROR Otherwise.

&Pn - Select Pulse Dial Make/Break Ratio

This command determines the make/break ratio used during pulse dialling.
It is only effective if the appropriate bit to enable
this command is set through the ConfigurACE program. If enabled, it will
override the make/break ratios in the OEM parameters
in ConfigurACE. The default is country-dependent. The parameter value, if
valid, is written to S28 bits 3 and 4.

&P0

Selects 39%-61% make/break ratio at 10 pulses per second. (Default.)

&P1

Selects 33%-67% make/break ratio at 10 pulses per second.

&P2

Selects 39%-61% make/break ratio at 20 pulses per second.

&P3

Selects 33%-67% make/break ratio at 20 pulses per second.

Result Codes:

OK n = 0 to 3.
ERROR Otherwise.

&Qn - Sync/Async Mode

This command is an extension of the &M command and is used to control the
connection modes permitted. It is used in conjunction
with S36 and S48. (Also, see \N.)

NOTE: When the &Q0 to &Q4 command is issued to select the mode, the
subsequent connect message will report the DCE speed regardless
of the W command and S95 settings.

Selects AutoSync operation. The value 100b is written to S27 bits 3,
1, and 0, respectively.

AutoSync operation, when used in conjunction with the Hayes Synchronous
Interface (HSI) capability in the DTE, provides synchronous
communication capability from an asynchronous terminal.

Starting AutoSync. Set registers S19, S20, and S25 to the desired values
before selecting AutoSync operation with &Q4. After
the CONNECT message is issued, the modem waits the period of time
specified by S25 before examining DTR. If DTR is on, the
modem enters the synchronous operating state; if DTR is off, the modem
terminates the line connection and returns to the asynchronous
command state.

Stopping AutoSync. AutoSync operation is stopped upon loss of carrier or
the on-to-off transition of DTR. Loss of carrier
will cause the modem to return to the asynchronous command state. An
on-to-off transition of DTR will cause the modem to return
to the asynchronous command state and either not terminate the line
connection (&D1 active) or terminate the line connection
(any other &Dn command active).

&Q5

The modem will try to negotiate an error-corrected link. The modem can
be configured using S36 to determine whether a failure
will result in the modem returning on-hook or will result in fallback to
an asynchronous connection. The value 101b is written
to S27 bits 3, 1, and 0, respectively. (Default.)

Result Codes:

&Rn - RTS/CTS Option

This selects how the modem controls CTS. CTS operation is modified if
hardware flow control is selected (see &K command).

&R0

In sync mode, CTS tracks the state of RTS; the RTS-to-CTS delay is
defined by S26. In async mode, CTS acts according to
V.25 bis handshake.

&R1

In sync mode, CTS is always ON (RTS transitions are ignored). In async
mode, CTS will only drop if required by flow control.
(Default.)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Sn - DSR Override

This command selects how the modem will control DSR. The parameter value,
if valid, is written to S21 bit 6.

&S0

DSR will remain ON at all times. (Default.)

&S1

DSR will become active after answer tone has been detected and
inactive after the carrier has been lost.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Tn - Test and Diagnostics

The modem will perform selected test and diagnostic functions according to
the parameter supplied. A test can be run only when
in an asynchronous operation in non-error-correction mode (normal or
direct mode). To terminate a test in progress, the escape
sequence must be entered first, except for parameters 7 and 8 (see Section
3.1.3). If S18 is non-zero, a test will terminate
automatically after the time specified by S18 and display the OK message.

&T0

Terminates test in progress. Clears S16.

&T1

Initiates local analog loopback, V.54 Loop 3. Sets S16 bit 0. If a
connection exists when this command is issued, the modem
hangs up. The CONNECT XXXX message is displayed upon the start of the test.

Requests a remote digital loopback (RDL), V.54 Loop 2, without self
test. If no connection exists, ERROR is returned. Sets
S16 bit 4 when the test is in progress. The CONNECT XXXX message is
displayed upon the start of the test.

&T7

Requests a remote digital loopback (RDL) ,V.54 Loop 2, with self test.
(In self test, a test pattern is looped back and
checked by the modem.) If no connection exists, ERROR is returned. When
the test is terminated either via expiration of S18,
or via the &T0 or H command, the number of detected errors is reported to
the DTE. Sets S16 bit 5 when the test is in progress.

&T8

Initiates local analog loopback, V.54 Loop 3, with self test. (In self
test, a test pattern is looped back and checked
by the modem.) If a connection exists, the modem hangs up before the test
is initiated. When the test is terminated either
via expiration of S18, or via the &T0 or H command, the number of detected
errors is reported to the DTE. Sets S16 bit 6 when
the test is in progress. This command may not be available in some
countries due to PTT restrictions.

&V - Display Current Configuration and Stored Profiles.

Reports the current (active) configuration, the stored (user) profiles,
and the first four stored telephone numbers. The stored
profiles and telephone numbers are not displayed if the NVRAM is not
installed or is not operational as detected by the NVRAM
test during reset processing.

If the NVRAM is not installed or is not operational as detected by the
NVRAM test, the following message is displayed:

NVRAM FAILED OR NOT INSTALLED

&Wn - Store Current Configuration

Saves the current (active) configuration (profile), including S registers,
in one of the two user profiles in NVRAM as denoted
by the parameter value. This command will yield an ERROR message if the
NVRAM is not installed or is not operational as detected
by the NVRAM test.

The current configuration is comprised of a list of storable parameters
illustrated in the &V command. These settings are restored
to the active configuration upon receiving an Zn command or at power up
(see &Yn command).

&W0

Store the current configuration as profile 0.

&W1

Store the current configuration as profile 1.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

&Xn - Select Synchronous Clock Source

Selects the source of the transmit clock for the synchronous mode of
operation. The parameter value, if valid, is written to
S27 bits 4 and 5.

In asynchronous mode, the transmit and receive clocks are turned OFF. In
synchronous mode, the clocks are turned ON with the
frequency of 1200 Hz or faster corresponding to the speed that is selected
for modem operation.

&X0

Selects internal timing. The modem generates the transmit clock signal
and applies it to the TXCLK output at the serial
interface.

&X1

Selects external timing. The local DTE sources the transmit clock
signal on the XTCLK input of the serial interface. The
modem applies this clock to the TXCLK output at the serial interface.

&X2

Selects slave receive timing. The modem derives the transmit clock
signal from the incoming carrier and applies it to the
TXCLK output at the serial interface.

Result Codes:

OK n = 0 to 2.
ERROR Otherwise.

&Yn - Designate a Default Reset Profile

Selects which user profile will be used after a hard reset.

&Y0

The modem will use profile 0.

&Y1

The modem will use profile 1.

Result Codes:

OK n = 0 to 1.
ERROR Otherwise.

&Zn=x - Store telephone number

The modem can store up to 4 (US) or 20 (W-class) telephone numbers. Each
telephone number dial string can contain up to 45
digits.

3.2.3. AT% Commands

Controls whether or not the modem will automatically monitor the line
quality and request a retrain (%E1) or fall back when
line quality is insufficient or fall forward when line quality is
sufficient (%E2). Applies to dial-up line only. The parameter
value, if valid, is written to S41 bits 2 and 6.

If enabled, the modem attempts to retrain for a maximum of 30 seconds.

%E0

Disable line quality monitor and auto-retrain. (Default.)

%E1

Enable line quality monitor and auto-retrain.

%E2

Enable line quality monitor and fallback/fall forward. (Not applicable
to RC96V24AC or RC14V24AC.)

Result Codes:

OK n = 0, 1, or 2.
ERROR Otherwise.

Fallback/Fall Forward. When %E2 is active, the modem monitors the line
quality (EQM). When line quality is insufficient, the
modem will initiate a rate renegotiation to a lower speed within the V.32
bis/V.32 modulation speeds. The modem will keep falling
back if necessary until the speed reaches 4800 bps. Below this rate, the
modem will only do retrains if EQM thresholds are
exceeded. If the EQM is sufficient for at least one minute, the modem will
initiate a rate renegotiation to a higher speed
within the V.32/V.32bis modulation speeds. The rate renegotiations will be
done without a retrain if a V.32bis connection is
established.

Speeds attempted during fallback/fall forward are those shown to be
available in the rate sequences exchanged during the initial
connection. Fallback/fall forward is available in error correction and
normal modes, but not in direct mode or synchronous
mode with external clocks.

%L - Line Signal Level

Returns a value which indicates the received signal level. The value
returned is a direct indication (DAA dependent) of the
receive level at the MDP, not at the telephone line connector. For
example, 009 = -9 dBm, 043 = -43 dBm, and so on.

Result Codes:

OK

%Q - Line Signal Quality

Reports the line signal quality (DAA dependent). Returns the higher order
byte of the EQM value. Based on the EQM value, retrain
or fallback/fall forward may be initiated if enabled by %E1 or %E2.

Example:

AT%Q
015

Result Codes:

OK If connected.
ERROR If not connected, or connected in 300 bps,
V.23, or fax modes.

%TTn - PTT Testing Utilities

Facilitates PTT testing of signal levels by providing continuous signals
regardless of whether the modem is connected or not.
The signal transmitted is in accordance with the parameter provided.

This is a range of commands that allow the user to initiate a series of
signals that are necessary for PTT approval. The signals
emitted include answer tone, modulation, carriers, and other pertinent
signals. A test is initiated upon receipt of an %TT
(T is a password), and the test is aborted when any keyboard character is
entered. The modem will continuously transmit the
tone or carrier according to the parameter supplied.

%TT00-%TT09

DTMF tone dial digits 0 to 9.

%TT0A

DTMF digit *.

%TT0B

DTMF digit A.

%TT0C

DTMF digit B.

%TT0D

DTMF digit C.

%TT0E

DTMF digit #.

%TT0F

DTMF digit D.

%TT10

V.21 channel 1 mark (originate) symbol.

%TT11

V.21 channel 2 mark symbol.

%TT12

V.23 backward channel mark symbol.

%TT13

V.23 forward channel mark symbol.

%TT14

V.22 originate (call mark) signalling at 600 bps.

%TT15

V.22 originate (call mark) signalling at 1200 bps.

%TT16

V.22 bis originate (call mark) signalling at 2400 bps.

%TT17

V.22 answer signalling (guard tone if PTT required).

%TT18

V.22 bis answer signalling (guard tone if required).

%TT19

V.21 channel 1 space symbol.

%TT20

V.32 9600 bps.

%TT21

V.32 bis 14400 bps.

%TT1A

V.21 channel 2 space symbol.

%TT1B

V.23 backward channel space symbol.

%TT1C

V.23 forward channel space symbol.

%TT30

Silence (on-line), i.e., go off-hook.

%TT31

V.25 answer tone.

%TT32

1800 Hz guard tone.

%TT33

V.25 calling tone (1300 Hz).

%TT34

Fax calling tone (1100 Hz).

%TT40

V.23 channel 2

%TT41

V.27 ter 2400 bps

%TT42

V.27 ter 4800 bps

%TT43

V.29 7200 bps

%TT44

V.29 9600 bps

%TT45

V.17 7200 bps long train

%TT46

V.17 7200 bps short train

%TT47

V.17 9600 bps long train

%TT48

V.17 9600 bps short train

%TT49

V.17 12000 bps long train

%TT4A

V.17 12000 bps short train

%TT4B

V.17 14400 bps long train

%TT4C

V.17 14400 bps short train

To permit output signal spectra measurement, data can be transmitted in
the absence of a received signal by setting S10 equal
to 255.
3.2.4. AT\ Commands

\Gn - Modem-to-Modem Flow Control (XON/XOFF)

In non-error correction mode, the modem enables or disables the generation
or recognition of modem-to-modem XON/XOFF flow control
according to the parameter supplied. The parameter value, if valid, is
written to S41 bit 3.

In error correction mode, the setting of modem-to-modem XON/XOFF flow
control is ignored. However, the serial port flow control
settings (AT&K) remain active during a reliable link.

Due to the buffering system used in the modem, modem-to-modem flow control
is normally disabled.

\G0

Disables modem-to-modem XON/XOFF flow control. (Default.)

\G1

Enables modem-to-modem XON/XOFF flow control.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

\Kn - Break Control

Controls the response of the modem to a break received from the DTE or the
remote modem or the \B command according to the
parameter supplied. The parameter value, if valid, is written to S40 bits
3, 4, and 5.

The response is different in three separate states.

The first state is where the modem receives a break from the DTE when the
modem is operating in data transfer mode:

Selects reliable (error-correction) mode. The modem will first attempt
a LAPM connection and then an MNP connection. Failure
to make a reliable connection results in the modem hanging up. (Forces
&Q5, S36=4, and S48=7.)

\N3

Selects auto reliable mode. This operates the same as \N2 except
failure to make a reliable connection results in the modem
falling back to the speed buffered normal mode. (Forces &Q5, S36=7, and
S48=7.)

\N4

Selects LAPM error-correction mode. Failure to make an LAPM
error-correction connection results in the modem hanging up.
(Forces &Q5 and S48=0.) Note: The -K1 command can override the \N4
command.

Result Codes:

3.3.2. AT\ Commands

\An - Select Maximum MNP Block Size

The modem will operate an MNP error corrected link using a maximum block
size controlled by the parameter supplied. The parameter
value, if valid, is written to S40 bits 6 and 7.

\A0

64 characters.

\A1

128 characters. (Default.)

\A2

192 characters.

\A3

256 characters.

Result Codes:

OK n = 0 to 3.
ERROR Otherwise.

\Bn - Transmit Break to Remote

In non-error correction mode, the modem will transmit a break signal to
the remote modem with a length in multiples of 100
ms according to parameter specified. If a number in excess of 9 is
entered, 9 is used. The command works in conjunction with
the \K command.

In error correction mode, the modem will signal a break through the active
error correction protocol, giving no indication
of the length.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.4. MNP 10 COMMANDS

3.4.1. AT) Commands

)Mn - Enable Cellular Power Level Adjustment

Enables or disables automatic adjustment of the transmit power level
during link negotiation for reliable links to accommodate
the signalling requirements of cellular telephone equipment. The parameter
value, if valid, is written to S40 bit 2. Note that
the @Mn command sets the initial transmit level.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

@Mn - Initial Cellular Power Level Setting

Sets the initial transmit power level for upshift at connect until line
conditions can be determined. @M0 corresponds to -26 dBm,
@M1 corresponds to -30 dBm, @M2 through @M10 correspond to -10 dBm, and
@M11 through @M31 correspond to -11 dBm to -31 dBm,
respectively. The parameter value, if valid, is written to S201 bits
0-4. (Default.)

@M0

-26 dBm (Default.)

@M1

-30 dBm

@M2

-10 dBm

@M3 - @M10

-10 dBm

@M11

-11 dBm

@M12

-12 dBm

...

@M30

-30 dBm

@M31

-31 dBm

Result Codes:

OK n = 0 to 31.
ERROR Otherwise.

:E - Compromise Equalizer Enable Command

Enables or disables the V.32 compromise equalizer. The parameter value, if
valid, is written to S201 bit 5. This command can
be used when the modem is attached to either a flat line or a cellular
connection.

:E0

Disables the equalizer

:E1

Enables the equalizer (Default)

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.5. W-CLASS COMMANDS

3.5.1. AT% Commands

%Fn - Split-Speed Direction Select

Determines which direction (transmit or receive) has the 75 bps channel,
and which has the 1200 bps channel. This command is
only valid if the \W1 command has been executed.

%F1

Selects 75Tx/1200Rx. Resets S28 bits 1 and 2. (Default.)

%F2

Selects 1200Tx/75Rx. Sets S28 bit 1 and resets S28 bit 2.

%Mn - AUXCTL Output Line Control

Configures the AUXCTL output line to be used to switch between primary and
auxiliary V.24 ports or to be used as a command/data
mode indicator (synchronous modes only).

%M0

Sets the AUXCTL line low. The line will go high when the modem enters
data mode if synchronous is selected.(i.e., for
modes &M1, &M2, or &M3). The line will return low at the end of data mode.
(Default.)

%M1

Sets the AUXCTL line high. The line will go low when the modem enters
data mode and will return high when the data mode
terminates and the command mode is entered.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.5.2. AT* Commands

*B - Display Blacklisted Numbers

This command requests the modem to return a list of blacklisted numbers to
the DTE. The format of the response is shown by
the example below. Permanently forbidden numbers as defined by country
requirements will not appear on this list. If no numbers
are blacklisted, only the OK result code is issued.

Example:

*C - Remote Configuration Password

This command instructs the modem to store a password. Following this
command, the response "ENTER PASSWORD" is generated, after
which the new password should be entered. The password supplied by a
remote modem wishing to reconfigure this local modem must
match the password stored by the local modem in response to the *C
command. The password must be alphanumeric and between 6
and 12 characters in length. This command works only with MNP connections.
The default password is QWERTY. (Also, see *E and
*R commands.)

* D - Display Delayed Numbers

This command causes the modem to send a list of the delayed numbers
together with the delay associated with each. The modem
will return a list of delayed telephone numbers as defined in the *B
command. The format of the response is shown by the example
below (delay times are shown hours:minutes:seconds). If no numbers are
delayed, only the OK result code is issued.

Example:

*NCnn - Country Select

Up to eight sets of country parameters may be stored in the EPROM. This
command checks to see if the entered number matches
the country code of one of the countries stored in the EPROM. If found,
the modem stores the location of that country in NVRAM.
Upon power up or a soft reset (Z command), the modem uses this location to
load the parameters for the corresponding country.
The default value of zero is used if no NVRAM is installed or the NVRAM
failed self test during reset.

Note: Automatic DAA country code recognition is enabled by the NC0 command
(the 0 country code is reserved for this function).
Automatic DAA country code recognition is disabled when by the NCnn
command selecting any other valid country code.

*NCnn Select country parameters corresponding to entered country code
(nn). The country codes are:

Result Codes:

OK If parameters corresponding to entered country
code are present in EPROM.
ERROR Otherwise.

*P - Store Callback Password

This command causes the modem to store a password and to store or delete a
corresponding telephone number in NVRAM. The password
will be used to match that supplied by a remote modem when secure access
is used. The modem will use the telephone number to
dial back the remote modem. The password must be between 6 and 12
characters in length. The telephone number length is 40 characters
maximum. If the number to be dialled back (along with the final colon) is
omitted, a password check will be performed, but
no callback will occur. Up to 20 password/telephone number pairs may be
entered.

AT*Pn: <password>:<number to be dialled back>

Parameters: 0 to 19.

Result Codes:

OK For parameters 0 to n and for dial
string of less than 41 digits.
ERROR Otherwise.

*R - Request Remote Configuration Mode

This command from the DTE requests that the local modem attempt to place
the remote modem in remote configuration mode. This
command will only be accepted if the local modem is in on-line command
state during an MNP error corrected link. Enter the
password (from 6 to 12 characters in length) after the REMOTE PASSWORD
prompt is displayed by the local DTE. The entered password
is inserted in a remote configuration request (a special MNP frame) and is
sent to the remote modem.

Following a successful request, indicated by the display of the !AT prompt
by the local DTE, the local DTE may send commands
to the remote modem. These commands, a subset of the normal commands
available, should be entered without the 'AT' header.
Some commands are prohibited and others may produce unpredictable results.
To exit the remote configuration mode, enter the
*E command or the escape sequence defined by register S202. The default
password is QWERTY. (Also, see * C and * E commands
and register S202.)

*Zn - Change Dial Codes:

In some countries, notably Norway, there exist two methods of pulse
dialing. This command allows the user to select one of
the two methods as appropriate for the application.

*Z0

Use dial code 0. (Default.)

*Z1

Use dial code 1.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.5.3. AT\ Commands

\F - Display Telephone Directory

The modem displays the telephone directory entries which were stored with
the &Z command.

\Wn - Split-Speed Operation

This command supports a split-speed DCE/DTE interface for applications
such as Viewdata terminals which require a transmit
speed of 75 bps and receive speed of 1200 bps at the DTE interface. The
parameter value, if valid, is written to S28 bit 0.

\W0

Disables split-speed mode. (Default.)

\W1

Enables split-speed mode. V.23 operation is also forced as though F3
had been entered. Note that %Fn command determines
the split screen direction.

Result Codes:

OK n = 0 or 1.
ERROR Otherwise.

3.6. CALLER ID COMMANDS

3.6.1. AT#CID Command

#CIDn - Caller ID

Enables or disables Caller ID.

#CID=0

Disables Caller ID. (Default.)

#CID=1

Enables Caller ID with formatted presentation to the DTE. The
modem will present the data items in a <Tag><Value> pair
format. The expected pairs are data, time, caller code (telephone number),
and name.

#CID=2

Enables Caller ID with unformatted presentation to the DTE. The
modem will present the entire packet of information,
excluding the leading U's, in ASCII printable hex numbers.

Result Codes:

OK n = 0 or 2.
ERROR Otherwise.

Inquiries

#CID?

Retrieves the current Caller ID mode from the modem.

#CID=?

Returns the mode capabilities of the modem in a list with each
element separated by commas.

Formatted Form Reporting

The modem presents the data in the <tag> <value> pair format as
described in the table below. Spaces are present on both
sides of the equal sign.
Tag Description

DATE

DATE = MMDD where MM is the month number (01 to 12) and DD is the
day number (01..31).

TIME

TIME = HHMM where HH is the hour number (00 to 23) and MM is the
minute number (00 to 59).

NMBR

NMBR = <number> or P or O where <number> is the telephone number of
the caller, where P indicates that the calling number
information is not available since the originating caller has requested
private service, and where O indicates that the calling
number information is not available or out of service at the calling
location.

Example of Formatted Form Reporting

2. The following example illustrates the case where the tag of the packet
is not recognized by the modem.

RING
MESG = 060342424231
RING
RING

Unformatted Form Reporting

The modem presents all information and packet control information found in
the message. The modem, however, excludes the leading
U's (channel seizure information) from the presentation. The packet is
presented in ASCII printable hex numbers, the modem
does not insert spaces, or line feeds, for formatting between bytes or
words of the packet.

The modem does not detect the checksum of the packet.

Example of Unformatted Form Reporting

RING
0412303332323234303539313435353132333435
RING
RING

3.7. AT COMMAND RESULT CODES

The modem responds to commands from the DTE and to activity on the line by
signalling to the DTE in the form of result codes.
The result codes that the modem can send are described below.

Two forms of each result code are available: long-form, an English-like
"verbose" response, and short-form, a data-like numeric
response (included in parentheses following the long-form). The long-form
code is preceded and terminated by the sequence <
CR> < LF>. The short-form is terminated by < CR>,
only with no preceding sequence.

If result messages are suppressed, nothing is returned to the DTE. The
long-form results codes can be modified by the OEM through
the ConfigurACE Configuration Utility Program. (See ConfigurACE
description.)

00- OK

The OK code is returned by the modem to acknowledge execution of a command
line.

01- CONNECT

The modem will send this result code upon connecting when:

The line speed is 300 bps and the modem has been instructed to report
the line speed to the DTE upon connecting, or

The DTE speed is 300 bps and the modem has been instructed to report
the DTE speed to the DTE upon connecting, or

The range of result code responses is restricted by the X command such
that no speed reporting is allowed.

02- RING

The modem sends this result code when incoming ringing is detected on the
line. What qualifies as a ring signal is determined
by country-dependent parameters, modifiable through ConfigurACE.

03- NO CARRIER

The modem sends this result code when attempting to establish a call if:

Ringback is detected and later ceases but no carrier is detected within
the period of time determined by register S7, or

No ringback is detected within the period of time determined by
register S7.

This result code is also used when the modem auto-disconnects due to loss
of carrier.

Under X0, if busy tone detection is enforced, this result code is used as
a response to the detection of busy or circuit busy.
Under X0, if dial tone detection is enforced or selected, this result code
is used to indicate that dial tone has not been
detected.

04- ERROR

The modem returns this result code if the command line contains a syntax
error or it is unable to execute a command contained
in the command line. It is issued if a command does not exist or if the
parameter supplied is outside the permitted range.

Under X0, X1, X2, and X3, this result is used instead of DELAYED and
BLACKLISTED.

05- CONNECT 1200

For X1, X2, X3, and X4, the modem sends this result code when:

The line speed is 1200 bps and the modem has been instructed to report
the line speed to the DTE upon connecting, or

The DTE speed is 1200 bps and the modem has been instructed to report
the DTE speed to the DTE upon connecting.

(Also, see the W command.)

06- NO DIALTONE

For X2 and X4, the modem sends this result code if it has been instructed
to wait for dial tone during dialling but none is
received.

07- BUSY

For X3 and X4, if busy tone detection is enforced, the modem sends this
result code when attempting to originate a call if
the busy (engaged) signal is detected on the line.

08- NO ANSWER

The modem sends this result code when attempting to originate a call if a
continuous ringback signal is detected on the line
until the expiration of the timer S7.

09- CONNECT 0600

For X1, X2, X3, and X4, the modem sends this result code when:

The line speed is 600 bps and the modem has been instructed to report
the line speed to the DTE upon connecting, or

The DTE speed is 600 bps and the modem has been instructed to report
the DTE speed to the DTE upon connecting.

10- CONNECT 2400

For X1, X2, X3, and X4, the modem sends this result code when:

The line speed is 2400 bps and the modem has been instructed to report
the line speed to the DTE upon connecting, or

The DTE speed is 2400 bps and the modem has been instructed to report
the DTE speed to the DTE upon connecting.

11- CONNECT 4800

For X1, X2, X3, and X4, the modem sends this result code when the DTE
speed is 4800 bps and the modem has been instructed to
report the DTE speed upon connecting.

12- CONNECT 9600

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 9600 bps and the modem has been
instructed to report the DTE speed to the DTE upon connecting.

13- CONNECT 7200

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 7200 bps and the modem has been
instructed to report the DTE speed to the DTE upon connecting.

14- CONNECT 12000

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 12000 bps and the modem has
been instructed to report the DTE speed to the DTE upon connecting.

15- CONNECT 14400

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 14400 bps and the modem has
been instructed to report the DTE speed to the DTE upon connecting.

16- CONNECT 19200

For X1, X2, X3, and X4, the modem returns this result code upon connecting
when the DTE speed is 19,200 bps and the modem has
been instructed to report the DTE speed upon connecting.

17- CONNECT 38400

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 38400 bps and the modem has
been instructed to report the DTE speed to the DTE upon connecting.

18- CONNECT 57600

For X1, X2, X3, and X4, the modem sends this result code upon connecting
when the DTE speed is 57600 bps and the modem has
been instructed to report the DTE speed to the DTE upon connecting.

22- CONNECT 75TX/1200RX

For X1, X2, X3, and X4, the modem returns this result code upon
establishing a V.23 originate connection when the modem has
been instructed to report the DCE speed upon connection.

23- CONNECT 1200TX/75RX

For X1, X2, X3, and X4, the modem returns this result code upon
establishing a V.23 answer connection when the modem has been
instructed to report the DCE speed upon connection.

24- DELAYED

For X4, the modem returns this result code when a call fails to connect
and the number dialled is considered 'delayed' due
to country blacklisting requirements.

32- BLACKLISTED

For X4, the modem returns this result code when a call fails to connect
and the number dialled is considered 'blacklisted'.

33- FAX

The modem returns this result code when a fax modem connection is
established in a facsimile mode.

35- DATA

The modem returns this result code when a data modem connection is
established in a facsimile mode.

40- CARRIER 300

The modem returns this result code when either a V.21 or Bell 103 carrier
has been detected on the line and carrier reporting
has been enabled. (See S95.)

44- CARRIER 1200/75

The modem sends this result code when the V.23 backward channel carrier
has been detected on the line and carrier reporting
has been enabled. (See S95 and X4.)

45- CARRIER 75/1200

The modem sends this result code when the V.23 forward channel carrier has
been detected on the line and carrier reporting
has been enabled. (See S95 and X4.)

46- CARRIER 1200

The modem sends this result code when either the high or low channel
carrier in either V.22 or Bell 212 mode has been detected
on the line and carrier reporting has been enabled. (See S95 and X4.)

47- CARRIER 2400

The modem sends this result code when either the high or low channel
carrier in V.22 bis mode has been detected on the line,
and carrier reporting has been enabled. (See S95 and X4.)

48- CARRIER 4800

The modem sends this result code when the 4800 bps data rate in V.32 bis
or V.32 mode has been detected on the line, and carrier
reporting has been enabled. (See S95 and X4.)

49- CARRIER 7200

The modem sends this result code when the 7200 bps data rate in V.32 bis
mode has been detected on the line, and carrier reporting
has been enabled. (See S95 and X4.)

50- CARRIER 9600

The modem sends this result code when the 9600 bps data rate in V.32 bis
or V.32 mode has been detected on the line, and carrier
reporting has been enabled. (See S95 and X4.)

51- CARRIER 12000

The modem sends this result code when the 12000 bps data rate in V.32 bis
mode has been detected on the line, and carrier reporting
has been enabled. (See S95 and X4.)

52- CARRIER 14400

The modem sends this result code when the 14400 bps data rate in V.32 bis
mode has been detected on the line, and carrier reporting
has been enabled. (See S95 and X4.)

66- COMPRESSION: CLASS 5

This message is sent to the DTE when the modem has connected in MNP Class
5 and COMPRESSION message reporting has been enabled.
(See S95 and X4.)

67- COMPRESSION: V.42 bis

This message is sent to the DTE when the modem has connected in V.42 bis
and COMPRESSION message reporting has been enabled.
(See S95 and X4.)

69- COMPRESSION: NONE

This message is sent to the DTE when the modem has connected without data
compression and COMPRESSION message reporting has
been enabled. (See S95 and X4.)

70- PROTOCOL: NONE

This message is sent to the DTE when the modem has connected without any
form of error correction, and the PROTOCOL message
reporting has been enabled. (See S95 and X4.)

77- PROTOCOL: LAPM

This message is sent to the DTE when the modem has connected in the V.42
LAPM mode of error correction, and PROTOCOL message
reporting has been enabled. (See S95 and X4.)

80- PROTOCOL: ALT

This message is sent to the DTE when the modem has connected in the MNP
mode of error correction, and PROTOCOL message reporting
has been enabled. (See S95 and X4.)

81- PROTOCOL: ALT-CELLULAR

This message is sent to the DTE when the modem has connected in the MNP 10
mode, and PROTOCOL message reporting has been enabled.
(See S95 and X4.)

+FC- FCERROR

This message is sent to the DTE when the modem has detected an error in
fax class 1 or fax class 2 mode.

4. S REGISTERS

The S registers are summarized in Table 4-1 along with their default
values. Registers denoted with an '*' in Table 4-1 may
be stored in one of the two user profiles by entering the &Wn command. One
of these profiles may be loaded at any time by using
the Zn command. Registers or register fields quoted as "reserved" are
reserved for current or future use by the firmware, or
are permanently overridden by PTT limitations. For the latter, control of
the equivalent functionality is available with ConfigurACE
Call Progress and Blacklisting options.

All bit-mapped registers are read-only. The appropriate AT command which
controls the relevant bits in the S-register should
be used to change the value.

4.1. FACTORY DEFAULTS

The factory default values are stored in ROM and are loaded into the
active configuration at power up or by the ATZn command.
In addition, the designated default profile is subsequently loaded, and
may change some of the factory default values. The
designated default profile can be changed by entering the &Yn command
where n is one of the two possible user profiles.

The defaults shown are those used by Rockwell in factory profiles zero and
one. These may be overwritten by the OEM with ConfigurACE
prior to placing the firmware in PROM. Minimum and maximum values may also
be imposed by ConfigurACE in response to country
PTT requirements.

* Register value may be stored in one of two user profiles with the &W
command.

4.2. S REGISTER DEFINITIONS

S0 - Number of Rings to Auto-Answer

Sets the number of the rings required before the modem automatically
answers a call. Setting this register to zero disables
auto-answer mode.

Range:

0-255 rings

Default:

0 (US models)
2 (W-class models)

S1 - Ring Counter

S1 is incremented each time the modem detects a ring signal on the
telephone line. S1 is cleared if no rings occur over an
eight second interval.

Range:

0-255 rings

Default:

0

S2 - Escape Character

S2 holds the decimal value of the ASCII character used as the escape
character. The default value corresponds to an ASCII '+'.
A value over 127 disables the escape process, i.e., no escape character
will be recognized.

Range:

0-255, ASCII decimal

Default:

43 (+)

S3 - Carriage Return Character

Sets the command line and result code terminator character. Pertains to
asynchronous operation only.

Range:

0-127, ASCII decimal

Default:

13 (Carriage Return)

S4 - Line Feed Character

Sets the character recognized as a line feed. Pertains to asynchronous
operation only. The Line Feed control character is output
after the Carriage Return control character if verbose result codes are
used

Range:

0-127, ASCII decimal

Default:

10 (Line Feed)

S5 - Backspace Character

Sets the character recognized as a backspace. Pertains to asynchronous
operation only. The modem will not recognize the Backspace
character if it is set to a value that is greater than 32 ASCII. This
character can be used to edit a command line. When the
echo command is enabled, the modem echoes back to the local DTE the
Backspace character, an ASCII space character and a second
Backspace character; this means a total of three characters are
transmitted each time the modem processes the Backspace character.

Range:

0-32, ASCII decimal

Default:

Sets the length of time, in seconds, that the modem will wait before
starting to dial after going off-hook when blind dialing.
This operation, however, may be affected by some ATX options according to
country restrictions. The "Wait for Dial Tone" call
progress feature (W dial modifier in the dial string) will override the
value in register S6.

For W-class models, S6 sets the length of time, in seconds, that the
modem will wait for dial tone when encountering a "W"
dial modifier before continuing with the next dial string parameter.

The modem always pauses for a minimum of 2 seconds, even if the value of
S6 is less than 2 seconds.

Range:

2-255 seconds

Default:

2 (US models)
4 (W-Class models)

S7 - Wait Time For Carrier After Dial, For Silence, or For Dial Tone After
"W" Dial Modifier (US Models)

Sets the length of time, in seconds, that the modem will wait for
carrier before hanging up. The timer is started when the
modem finishes dialing (originate), or 2 seconds after going off-hook
(answer). In originate mode, the timer is reset upon
detection of answer tone if allowed by country restrictions.

Sets the length of time, in seconds, that modem will wait for silence
when encountering the @ dial modifier before continuing
with the next dial string parameter.

For US models, S7 sets the length of time, in seconds, that the modem
will wait for dial tone when encountering a "W" dial
modifier before continuing with the next dial string parameter.

Range:

1-255 seconds

Default:

50

S8 - Pause Time For Dial Delay

Sets the time, in seconds, that the modem must pause when the "," dial
modifier is encountered in the dial string.

Range:

0-255 seconds

Default:

2

S9 - Carrier Detect Response Time

Sets the time, in tenths of a second, that the carrier must be present
before the modem considers it valid and turns on RLSD.
As this time is increased, there is less chance to detect a false carrier
due to noise from the telephone line.

Range:

1-255 tenths of a second

Default:

6 (0.6 second)

S10 - Lost Carrier To Hang Up Delay

Sets the length of time, in tenths of a second, that the modem waits
before hanging up after a loss of carrier. This allows
for a temporary carrier loss without causing the local modem to
disconnect. When register S10 is set to 255, the modem functions
as if a carrier is always present.

The actual interval the modem waits before disconnecting is the value in
register S10 minus the value in register S9. Therefore,
the S10 value must be greater than the S9 value or else the modem
disconnects before it recognizes the carrier.

Range:

1-255 tenths of a second

Default:

14 (1.4 seconds)

S11 - DTMF Tone Duration

Sets the duration of tones in DTMF dialing (US models only). This value
has no effect on pulse dialing.

For W-class models, this parameter is a country parameter loaded by
ConfigurACE.

Range:

50-255 milliseconds

Default:

95 (95 milliseconds)

S12 - Escape Code Guard Time

Defines the maximum period, in fiftieths of a second, allowed between
consecutive asynchronous escape characters (+) for the
escape sequence to be considered valid.

S17 - Reserved

S18 - Test Timer

Sets the length of time, in seconds, that the modem conducts a test
(commanded by &Tn) before returning to the command mode.
If this register value is zero, the test will not automatically terminate;
the test must be terminated from the command mode
by issuing an &T0 or H command. When S18 is non-zero, the modem returns
the OK message upon test termination.

Range:

0-255 seconds

Default:

0

S19 - AutoSync Registers

Defines the options for AutoSync operation (see &Q4 command). S19 must be
set to the desired value before &Q4 is issued.

S24 - Sleep Inactivity Timer

Sets the length of time, in seconds, that the modem will operate in normal
mode with no detected telephone line or DTE line
activity before entering low-power sleep mode. The timer is reset upon any
DTE line or telephone line activity. If the S24
value is zero, neither DTE line nor telephone inactivity will cause the
modem to enter the sleep mode.

Range:

0-255 seconds

Default:

0

S25 - Delay To DTR

Sets the length of time that the modem will ignore DTR for before hanging
up. Its units are seconds for synchronous modes and
one hundredths of a second for other modes.

Range:

0-255 (1 second for synchronous modes 1; 0.01 second otherwise )

Default:

5

S26 - RTS to CTS Delay

Sets the time delay, in hundredths of a second, before the modem turns CTS
ON after detecting an OFF-to-ON transition on RTS
when &R0 is commanded. Pertains to synchronous operation only.

S29 - Flash Dial Modifier Time

Sets the length of time, in units of 10 ms, that the modem will go oh-hook
when it encounters the flash (!) dial modifier in
the dial string. The time can be limited as it is a country dependent
parameter.

Range:

0-255 10 ms intervals

Default:

0 (disabled)

S30 - Disconnect Inactivity Timer

Sets the length of time, in tens of seconds, that the modem will stay
online before disconnecting when no data is sent or received.
In error-correction mode, any data transmitted or received will reset the
timer. In other modes, any data transmitted will
reset the timer. The timer is inoperative in synchronous mode.

S32 - XON Character

Range:

Default:

S33 - XOFF Character

Sets the value of the XOFF character.

Range:

0-255 , ASCII decimal

Default:

19 (13h)

S34-S35 - Reserved

S36 - LAPM Failure Control (Applies to ECC Models Only)

Default:

7 (00000111b)

Bit 0-2 - This value indicates what should happen
upon a LAPM failure. These fallback options
are initiated immediately upon connection if
S48=128. If an invalid number is entered,
the number is accepted into the register,
but S36 will act as if the default value has
been entered.
0 Modem disconnects.
1 Modem stays on-line and a Direct mode
connection is established.
2 Reserved.
3 Modem stays on-line and a Normal mode
connection is established.
4 An MNP connection is attempted and if
it fails, the modem disconnects.
5 An MNP connection is attempted and if
it fails, a Direct mode connection is
established.
6 Reserved.
7 An MNP connection is attempted and if
it fails, a Normal mode connection is
established. (Default)
Bit 3-7 - Reserved

S37 - Desired Line Connection Speed

Default:

0

Bit 0-3 - Desired line connection speed. This is
interlinked with the Fn command. If an invalid
number is entered, the number is accepted into
the register, but S37 will act as if the default
value has been entered.
0 Attempt auto mode connection (F0). (Default)
1-3 Attempt to connect at 300 bps (F1).
4 Reserved.
5 Attempt to connect at 1200 bps (F4).
6 Attempt to connect at 2400 bps (F5).
7 Attempt to connect at V.23 (F3).
8 Attempt to connect at 4800 bps (F6).
9 Attempt to connect at 9600 bps (F8).
10 Attempt to connect at 12000 bps (F9).
11 Attempt to connect at 14400 bps (F10).
12 Attempt to connect at 7200 bps (F7).
Bit 4-7 - Reserved

S38 - Delay Before Forced Hang Up

This register specifies the delay between the modem's receipt of the H
command to disconnect (or ON-to-OFF transition of DTR
if the modem is programmed to follow the signal), and the disconnect
operation. Applicable to error-correction connection only.
This register can be used to ensure that data in the modem buffer is sent
before the modem disconnects.

If S38 is set to a value between 0 and 254, the modem will wait that
number of seconds for the remote modem to acknowledge
all data in the modem buffer before disconnecting. If time expires before
all data is sent, the NO CARRIER result code will
be issued to indicate that data has been lost. If all data is transmitted
prior to time-out, the response to the H0 command
will be OK.

If S38 is set to 255, the modem does not time-out and continues to
attempt to deliver data in the buffer until the connection
is lost or the data is delivered.

Range:

Default:

S48 - V.42 Negotiation Action

The V.42 negotiation process determines the capabilities of the remote
modem. However, when the capabilities of the remote
modem are known and negotiation is unnecessary, this process can be
bypassed if so desired.

Range:

0, 7, or 128 If an invalid number is entered, it is accepted into
the S register, but S48 will act as if 128 has been
entered.

Default:

7

S48=0 Disable negotiation; bypass the detection and
negotiation phases; and proceed with LAPM.
S48=7 Enable negotiation. (Default.)
S48=128 Disable negotiation; bypass the detection and
negotiation phases; and proceed at once with the
fallback action specified in S36. Can be used to
force MNP.

S80 - Soft-Switch Functions

S80 is applicable only if the EPROM has been so customized by ConfigurACE.
S80 bits are the "soft" equivalent of four hardware
input signals. The hardware signal is indicated corresponding to each bit.

S82 - Break Handling Options

Break signals provide a way for the user to get the attention of the
remote modem. The break type depends on the specific application.
LAPM specifies three methods of break signal handling: in sequence,
expedited, and destructive. If an invalid number is entered,
it is accepted into the S register, but S82 will act as if the default
value has been entered.

Range:

3, 7, or 128

Default:

128

S82=3 Expedited: Modem sends a break immediately; data
integrity is maintained both ahead of and after
the break.
S82=7 Destructive: Modem sends a break immediately; data
being processed by each modem at the time of the
break is destroyed.
S82=128 In sequence: Modem sends a break in sequence with any
transmitted data; data integrity is maintained both
ahead of and after the break. (Default.)

S86 - Call Failure Reason Code

When the modem issues a NO CARRIER result code, a value is written to this
S register to help determine the reason for the
failed connection. S86 records the first event that contributes to a NO
CARRIER message. The cause codes are:

Range:

0, 4, 5, 9, 12, 13, or 14

Default:

-

S86=0 Normal disconnect, no error occurred.
S86=4 Loss of carrier.
S86=5 V.42 negotiation failed to detect an error-correction
modem at the other end.
S86=6 No response to feature negotiation.
S86=7 This modem is asynchronous only; the other modem is
synchronous only.
S86=8 No framing technique in common.
S86=9 The modems could not find a common protocol.
S86=10 Bad response to feature negotiation.
S86=11 No sync information from remote modem.
S86=12 Normal disconnect initiated by the remote modem.
S86=13 Remote modem does not respond after 10 re-transmissions
of the same message.
S86=14 Protocol violation.

S91 - PSTN Transmit Attenuation Level

Sets the transmit attenuation level from 0 to 15 dBm for the PSTN mode,
resulting in a transmit level from 0 to -15 dBm, In
some countries, the transmit level may not be changed and there are checks
to prevent transmit attenuation level change using
ConfigurACE.

Range:

0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)

Default:

10 (-10 dBm transmit level.)

S92 - Fax Transmit Attenuation Level

Sets the transmit attenuation level from 0 to 15 dBm for the fax mode,
resulting in a transmit level from 0 to -15 dBm. In
some countries, the transmit level may not be changed and there are checks
to prevent transmit attenuation level change using
ConfigurACE.

Range:

0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.)

Default:

10 (-10 dBm transmit level.)

S95 - Extended Result Codes

The bits in this register can be set to override some of the Wn command
options. A bit set to a 1 in this register will enable
the corresponding result code regardless of the Wn setting. Also, refer to
Table 3-1.

S99 - Leased Line Transmit Level

Sets the transmit level, in dBm, for the leased line mode. In some
countries this cannot be changed and there are checks to
prevent transmit level change.

Range:

0 to -15 dBm

Default:

10

S201 - Cellular Transmit Level

The bits in this register can be set to override some of the Wn command
options. A bit set to a 1 in this register will enable
the corresponding result code regardless of the Wn setting. Also, refer to
Table 3-1.

Default:

S202 - Remote Access Escape Character

S202 holds the decimal value of the ASCII character used as the escape
character in the escape sequence from on-line to Remote
Access. S202 works similar to S2 except that the S2 escape character is
used in the escape sequence from on-line to the command
mode.

Range:

0-255, ASCII decimal

Default:

170 (Escape disabled)
A value over 127 disables the escape process, i.e., no escape character
will be recognized. The default S202 value of 170 disables
the escape process to Remote Access (whereas the default S2 value enables
escape to command mode). If 128 is subtracted from
170 (i.e., bit 7 is reset), the resulting 42 is the ASCII code for the '*'
character. The '*' character is commonly used for
the Remote Access escape character.

The Remote Access escape sequence consists of four characters with a fixed
escape guard time of 1 second. Only the character
selected by S202 is valid. When '*' is used for the escape character, the
escape sequence is '****'.

The Remote Access escape sequence works when the modems are connected in
any mode (normal, LAPM or MNP) except direct mode.
The modem on which the remote commands are typed (the "local modem") does
not need any special code associated with the remote
configuration. The "remote modem" (whose configuration will be modified
remotely) must have Remote Configuration Mode (RCM)
enabled (bit 2 of S80).

The escape sequence entered by the user on the local modem is recognized
by the remote modem, which then sends a message to
the local mode prompting for entry of the "remote password". From then on,
operation is similar to RCM except for slight differences
of presentation. The remote modem will send a ">" prompt before each AT
command. The user must type the AT prefix before the
command(s), which is not required by RCM. Several commands on the same
line can be accepted.

Some potentially hazardous AT commands are barred in Remote Access: ATO,
ATZ, AT&T, AT\B, AT*C, AT*L, AT*P, and ATZ. (Note
that ATA and ATD are automatically barred because the modem is already
connected.)

To exit Remote Access, enter command AT*X. Upon exiting Remote Access, the
normal data link is re-established and the "CONNECT"
message is issued to the DTE. (Note that in RCM, exit is to the command
mode, but actually, in both cases, return is to the
previous state before entering Remote Access/RCM). AT*R and AT*E commands
also operate the same as in RCM.

Remote Access can be exited by typing a remote ATH command. The connection
will be terminated and a "NO CARRIER" response will
be issued from the local modem to the DTE since the hangup was actually
performed by the remote modem.

5. V.25 BIS COMMAND SET

Modem operation may be controlled through the use of the V.25 bis command
set. This is implemented by command, response, and
circuit signalling providing addressed call and/or answer via circuit
108/2 in accordance with V.25 bis. V.25 bis is a CCITT
recommendation that defines a method of exchanging commands and
indications across a DTE interface (EIA-232/V.24). V.25 bis
defines modem behavior only while the modem is disconnected from the line,
or while the modem is off-hook and is attempting
to establish a connection. The following terms are used in the V.25 bis
description.

COMMAND:

An instruction issued by the DTE to the modem as part of the
automatic calling procedure.

INDICATION:

A response message issued by the modem to the DTE as part of
the automatic calling procedure.

PARAMETER:

A variable which may accompany commands or indications. In
general, more than one parameter may be used in a command
or indication.

5.1. DTE/DCE INTERCHANGE CIRCUITS

Communication between the DTE and modem is half duplex.

The DTE is the 'master' and the modem is the 'slave'. Only the DTE
initiates V.25 bis communications, while the modem just
responds.

When the modem is in data transfer mode after the connection has been
established, the modem is no longer in V.25 bis mode.

5.2. FORMATS FOR COMMANDS AND INDICATIONS

The modem will accept commands either in synchronous mode HDLC (NRZ or
NRZI) , BSC, or in asynchronous mode. The command set
conforms to the CCITT recommendation with two extensions for asynchronous
mode.

5.2.1. Synchronous Signalling

The modem can automatically detect and switch from HDLC framing to BSC
framing.

HDLC Frames

HDLC frames, commands, and indications are HDLC frames with data fields
called messages.

Framing Rules

Frames may be preceded and followed by any data including additional flags.

A frame with an address, control, or FCS field error is invalid. A frame
with more than 60 characters in the message field
is invalid. A frame with 3 or less characters in the message field is
rejected with the INV indication.

Invalid frames are ignored.

For every valid command frame received, the modem responds with exactly
one indication if the connection is not completed,
and no indication if the connection is completed.

When the modem receives a valid command frame, it will ignore another
command frame until it has completed sending its indication
back to the attached DTE, or until the connection is terminated, whichever
occurs last.

The modem can accept a valid command frame that follows an invalid frame
if there is a pause of at least 2 bit times between
the end of the invalid frame and the start of the valid frame.

The modem automatically detects whether each command frame is NRZ or NRZI
encoded and follows suit for its indication.

Command and indication frames contain inserted zero bits as required by
HDLC. The receiving entity (modem or DTE) strips out
these extra bits.

BSC Frames

The format for synchronous character oriented format shall be in
accordance with ISO 1745.

SYN

16h

STX

02h

MESSAGE Data

Must be an integer number of 8-bit characters between 3 and
60.

ETX

83h

Framing Rules

Frames may be preceded and followed by any data including additional SYN
characters.

A frame with a parity error is invalid. A frame with more than 60
characters in the message field is invalid. A frame with
3 or less characters in the message field is invalid. An invalid frame
will be rejected with the INV indication.

For every valid command frame received, the modem responds with exactly
one indication if the connection is not completed,
and no indication if the connection is completed. The modem does not
recognize or send any of the short 'ack' type messages
used in character oriented protocols.

When the modem receives a valid command frame, it will ignore another
command frame until it has completed sending its indication
back to the attached DTE, or until the connection is terminated, whichever
occurs last.

The modem can accept a valid command frame that follows an invalid frame
if there is a pause of at least 2-bit times between
the end of the invalid frame and the start of the valid frame.

5.2.2. Asynchronous Signalling

The format for the asynchronous character oriented format is:

MESSAGE <CR> <LF>

The default data rate for commands and parameters is the maximum data rate
permitted by the modem.

The message field can contain between 3 and 60 8-bit characters (7-bit IA5
per T.50 plus odd parity per V.4) which define the
parameters. Each frame can contain only one command followed by multiple
parameters as will fill the limit.

Command/Indication Exchange Protocol

The modem will ignore any command issued with incorrect parity. The modem
will ignore a command issued from the DTE before
it has completed execution of the previous command and given an
appropriate response. The modem will ignore a command from
the DTE while it is sending an indication to the DTE.

A command received with a message field of less than 3 characters or more
than 60 characters is regarded as an error in the
message and will result in the negative acknowledgment of the command by
the return of the invalid message (INV).

DTE Adaption

In asynchronous mode, the modem performs an autobaud/autoparity/autolength
function on the first characters received following
a Power-On Reset or <cntl> Z. If the modem receives a <CR> <LF> sequence,
it is able to calculate the speed, parity, and the
word length. If the modem receives only a <CR> character, it will
calculate the speed but retain the existing parity and word
length values. If the modem receives neither of these characters, it will
continue to use the existing values for speed, parity,
and word length. If no previous speed, parity, and/or length information
is available, the modem defaults to 7-bit even operation
at 9600 bps. The autolength/autoparity facility is capable of detection of
7- or 8-bit characters of even, odd, or no parity
with one stop bit. The modem then accepts and sends characters according
to this selection of speed, parity, and length. The
adaption algorithm is re-initialized by the next OFF-to-ON transition of
CT108/2.

In HDLC mode, the modem detects when DTE sends in NRZ or NRZI format, and
adjusts its indication format accordingly.

5.2.3. V.25 bis Escape Code Sequence

An escape sequence function for V.25 bis asynchronous operation is
provided which operates exactly like the AT escape sequence.
(See Section 3.1.)

5.3. STANDARD V.25 BIS COMMANDS

The following commands are implemented, and parameters applicable to each
command are noted following the description of the
command.

CIC - Connect Incoming Call

The modem goes on-line in answer mode cancelling any DIC command
previously issued. If no incoming call is present, the modem
issues the invalid (INV) message.

CRI - Call Request with Number and Identification

The modem goes on-line, dials according to the dial string entered, and
attempts to establish a connection in the same manner
as the CRN command except a ";" character and an identification character
string can be inserted after the dial string. However,
everything after the ";" character is ignored, i.e., the identification is
not sent.

x..x Dial string:

a string of dial characters (see CRN).

; Separator:

inserted between dial string and identification.

Example:

CRN 234-1234;4567
VAL

CRN - Call Request with Number

The modem goes on-line, dials according to the dial string entered, and
attempts to establish a connection. The following dial
modifiers are valid:

0-9

Digits 0 to 9.

*

The 'star' digit: Tone dialling only.

#

The 'gate' digit: Tone dialling only.

T

Select tone dialling: Affects current and subsequent dialling.

P

Select pulse dialling: Affects current and subsequent dialling.

<

Short dial pause: Period controlled by S8: The modem will pause before
dialling the digits following "<."

=

Long dial pause: Period twice as long as the short dial pause.

:

Wait for dial tone: The modem will wait for dial tone before dialling
the digits following ":".

The modem returns this message when a connection has been established. The
message may be followed by a value indicating the
connection speed.

Example:

CNX 9600

DLC

- Delayed Call

The modem returns this message when a call fails to connect and the number
dialled is considered 'delayed'. The message indicates
the delay (in minutes) before the call may be re-attempted as shown in the
following example:

DLCn (n = delay in minutes)

This message will be preceded by the message indicating call failure.

INC

- Incoming Call

The modem sends this message when incoming ringing is detected on the line.

INV

- Invalid Command

The modem sends this message if the command line contains a syntax error,
or if the modem is unable to execute the command.

VAL

- Valid Command

The modem sends this message when it successfully executes the command
issued and there is no other applicable response (message
or circuit transition).